Affiliation: Department of Life Sciences, School of Pharmacy, International Medical University, 57000 Kuala Lumpur, Malaysia.

ABSTRACTGut microbiota plays an important role in mammalian host metabolism and physiological functions. The functions are particularly important in young children where rapid mental and physical developments are taking place. Nevertheless, little is known about the gut microbiome and the factors that contribute to microbial variation in the gut of South East Asian children. Here, we compared the gut bacterial richness and composition of pre-adolescence in Northern Malaysia. Our subjects covered three distinct ethnic groups with relatively narrow range of socioeconomic discrepancy. These included the Malays (n = 24), Chinese (n = 17) and the Orang Asli (indigenous) (n = 20). Our results suggested a strong ethnicity and socioeconomic-linked bacterial diversity. Highest bacterial diversity was detected from the economically deprived indigenous children while the lowest diversity was recorded from the relatively wealthy Chinese children. In addition, predicted functional metagenome profiling suggested an over-representation of pathways pertinent to bacterial colonisation and chemotaxis in the former while the latter exhibited enriched gene pathways related to sugar metabolism.

Mentions:
In order to examine the taxonomic composition of the faecal sample in detail, 6 replicates from each group were randomly selected for 16S pyrosequencing (see Fig. 1). From a total of 73,934 filtered sequences, 4,787 unique sequences were detected. Sample coverage for all samples was in the range of 97–99% (Fig. S1). Using a 97% sequence homology cut-off, significantly higher OTUs were detected in Orang Asli samples as opposed to Malays and Chinese (Table 1). Additionally, the alpha diversity measures applied here suggested a greater sequence richness and evenness in Orang Asli samples in comparison to others. The beta diversity measures including AMOVA (Table S3) and PCO (Fig. 2) further suggested that the Orang Asli encompassed a distinct community structure and composition. Overall, Firmicutes and Bacteroidetes were the dominated phyla while Feacabacterium and Prevotella are the dominant genera in the faeces of the studied cohort (Fig. 3, Fig. S2). However, the differences in faecal microbiota between Orang Asli against Chinese and Malay children can be attributed to the differences in Aeromonadales, and unclassified order under Bacteroidetes and Deltaproteobacteria, and unclassified genus under Ruminococcaceae (Table 3). Interestingly, no significant difference in bacterial taxonomic composition was detected between Malays and Chinese despite relative higher socioeconomic status and hygiene awareness in the latter in comparison to the former.

Mentions:
In order to examine the taxonomic composition of the faecal sample in detail, 6 replicates from each group were randomly selected for 16S pyrosequencing (see Fig. 1). From a total of 73,934 filtered sequences, 4,787 unique sequences were detected. Sample coverage for all samples was in the range of 97–99% (Fig. S1). Using a 97% sequence homology cut-off, significantly higher OTUs were detected in Orang Asli samples as opposed to Malays and Chinese (Table 1). Additionally, the alpha diversity measures applied here suggested a greater sequence richness and evenness in Orang Asli samples in comparison to others. The beta diversity measures including AMOVA (Table S3) and PCO (Fig. 2) further suggested that the Orang Asli encompassed a distinct community structure and composition. Overall, Firmicutes and Bacteroidetes were the dominated phyla while Feacabacterium and Prevotella are the dominant genera in the faeces of the studied cohort (Fig. 3, Fig. S2). However, the differences in faecal microbiota between Orang Asli against Chinese and Malay children can be attributed to the differences in Aeromonadales, and unclassified order under Bacteroidetes and Deltaproteobacteria, and unclassified genus under Ruminococcaceae (Table 3). Interestingly, no significant difference in bacterial taxonomic composition was detected between Malays and Chinese despite relative higher socioeconomic status and hygiene awareness in the latter in comparison to the former.

Bottom Line:
Here, we compared the gut bacterial richness and composition of pre-adolescence in Northern Malaysia.Our results suggested a strong ethnicity and socioeconomic-linked bacterial diversity.In addition, predicted functional metagenome profiling suggested an over-representation of pathways pertinent to bacterial colonisation and chemotaxis in the former while the latter exhibited enriched gene pathways related to sugar metabolism.

Affiliation:
Department of Life Sciences, School of Pharmacy, International Medical University, 57000 Kuala Lumpur, Malaysia.

ABSTRACTGut microbiota plays an important role in mammalian host metabolism and physiological functions. The functions are particularly important in young children where rapid mental and physical developments are taking place. Nevertheless, little is known about the gut microbiome and the factors that contribute to microbial variation in the gut of South East Asian children. Here, we compared the gut bacterial richness and composition of pre-adolescence in Northern Malaysia. Our subjects covered three distinct ethnic groups with relatively narrow range of socioeconomic discrepancy. These included the Malays (n = 24), Chinese (n = 17) and the Orang Asli (indigenous) (n = 20). Our results suggested a strong ethnicity and socioeconomic-linked bacterial diversity. Highest bacterial diversity was detected from the economically deprived indigenous children while the lowest diversity was recorded from the relatively wealthy Chinese children. In addition, predicted functional metagenome profiling suggested an over-representation of pathways pertinent to bacterial colonisation and chemotaxis in the former while the latter exhibited enriched gene pathways related to sugar metabolism.